Orhon River

River, north-central Mongolia. Some 700 mi (1,130 km) long, it rises from the slopes of the Hangayn Mountains and flows east, then north past the ruins of Karakorum. The 8th-century funerary stelae discovered in the river's valley in 1889 contain some of the oldest known Turkic writing, called the Orhon inscriptions. The river is navigable for shallow-draft vessels only in July and August.